R6E: Any clue on what is the expected i9-7940X overclock?

[Inkar]

Hi,

Does anyone have a clue about what is the all core expected i9-7940X (non-avx) overclock range with the Rampage VI Extreme and an AIO?.
I know nothing is guaranteed other than the factory specs. I just can't find any reviews with this kind of data for the 7940X.


Thanks.

[Marko911]

Silent Scone wrote:
Interesting comment, are you speaking vicariously or have you done any testing yourself?

Sorry for the late replay.This forum doesn't give me notification when someone replay to me.I did tested OC on my i9 7900x.Running custom loop with two 60mm thick HL rad SR2420mm push only and SR2 360 in push pull in full tower case thermaltake View 71.I have rockit99 delidd tool,which I will be using with my RVIE monoblock from EK as soon as my Singularity Computer parts arrive,I don't have time now to disassemble my loop 2x in one month.So I have info only on stock TIM under IHS of 7900x.I can hit 4,3Ghz on 8 cores and 2 core at 4,6Ghz and it runs stable-ish.For me true stability testing is Asus Realbench and HandBrake H264x.
Temps rose to 91C,tjmax 105.VRM doesn't hit above 80C on RVIE with heatsink.
Supermacy Evo do make good contact with IHS but heat transfer is really really poor.(as it was with my kabby lake 7700k,which before delidding could hit unstable 4,6 after delidding could hit 5,0 at 1,45V and temps never rose above 75C in prime95 26.6 non AVX)-survived Realbench,IBT for 2,5hours ,Handbrake H264x and prime95 26.6 for 5h.-Damn,that system was blazing fast,boot in seconds...
So i9 7900x is really sluggish compared to kabylake,but I hope to see after delidding some improvement .Also,my G.skill 16gb ram which I used for testing couldn't hit XMP 3000mhz,So I had to dial down to 2692Mhz.

[Brighttail]

I don't know max safe voltage, because personally I think you'll run into a heat issue before you reach that voltage, especially with that many cores. That being said, I know places like Silicon Lottery keeps all of its HCC x299s max at 1.25v for full stress testing. I think there is room to go above that for normal every day computing/gaming but I wouldn't personally want to go much above that on a 24/7 cycle.

[Silent_Scone]

I've just picked up a 7940X and using heavy custom water, I'll let you know how I get on. It's a fairly disregarded SKU due being in the middle of the pack. I'd be happy with 4.6, anything above this is a bonus. As for self imposed voltage limits, I wouldn't stray over 1.3v for light workloads (non AVX). 1.25v for high current workloads

[Skunkfoo]

Silent Scone wrote:
I've just picked up a 7940X and using heavy custom water, I'll let you know how I get on. It's a fairly disregarded SKU due being in the middle of the pack. I'd be happy with 4.6, anything above this is a bonus. As for self imposed voltage limits, I wouldn't stray over 1.3v for light workloads (non AVX). 1.25v for high current workloads

Thanks, do keep my updated on your OC adventures. My 7940x gets 4.6 no problem with HWInfo reporting highest voltages at 1.246. I'm sure I could get 4.7 stable around 1.28-1.3... already got it fairly stable at 1.282 using manual mode. I didn't want to go higher before knowing what a safe voltage was. As far as temps I have lots of room in my custom loops. I'm more concerned about ruining what I think is a decent chip.

Back in the day before I thought all you had to do was worry about temps, I have been running my 4930K at a constant fixed frequency of 4.4 GHz and 1.408 manual voltage since 2014. I'm not about to send 1.4+ or even 1.3+ to my new 7940x anytime soon.

[Silent_Scone]

Skunkfoo wrote:
Thanks, do keep my updated on your OC adventures. My 7940x gets 4.6 no problem with HWInfo reporting highest voltages at 1.246. I'm sure I could get 4.7 stable around 1.28-1.3... already got it fairly stable at 1.282 using manual mode. I didn't want to go higher before knowing what a safe voltage was. As far as temps I have lots of room in my custom loops. I'm more concerned about ruining what I think is a decent chip.

Back in the day before I thought all you had to do was worry about temps, I have been running my 4930K at a constant fixed frequency of 4.4 GHz and 1.408 manual voltage since 2014. I'm not about to send 1.4+ or even 1.3+ to my new 7940x anytime soon.

This CPU can do 4.7Ghz non AVX with 1.25v and Mesh 3Ghz at around 1.04v. Temps help, though. 4.6 is still very good for 14 cores.

[Skunkfoo]

Silent Scone wrote:
This CPU can do 4.7Ghz non AVX with 1.25v and Mesh 3Ghz at around 1.04v. Temps help, though. 4.6 is still very good for 14 cores.

4.7 @ 1.25... I'm jealous. 4.7 seemed so much faster than 4.6. Is your chip delidded? Are you saying that if you ran AVX your OC isn't stable anymore?

I will attempt 4.7 again once I teardown my loop to clean it out... EK failed me and a brand new loop got all gunked up on day 1 after I added the EK CryoFuel clear concentrate.

[Silent_Scone]

AVX offsets are currently 2 for AVX and 3 for AVX 512. 4.7 is non AVX. No, my chip is not delidded yet. If you're aiming for 4.7GHz AVX you might be hunting a while. 4.6 is still good for 14 cores.

That's unfortunate! I only ever use clear premix personally. EC6 from XSPC.*

[Skunkfoo]

Silent Scone wrote:
AVX offsets are currently 2 for AVX and 3 for AVX 512. 4.7 is non AVX. No, my chip is not delidded yet. If you're aiming for 4.7GHz AVX you might be hunting a while. 4.6 is still good for 14 cores.

That's unfortunate! I only ever use clear premix personally. EC6 from XSPC.*

Yeah I used clear to avoid dye separation and the gunking up I ended up experienced anyways.

I will try 4.7 on 2 best cores and see if I can get it stable at 1.26 on those 2. My build is not for 24/7 cpu number crunching, just a game here and there and Microsoft office stuff. But I do run a few Virtual Machines simultaneously and i like to give them lots of cores and ram. The VMs themselves arent usually stressed either. I do a lot of coding and like my builds/compilations to go really fast and I find high CPU frequency is a big plus.

[Protocol]

Figured I would share my experience with the 7940X so far. Granted it's only been about a week since I've built this, after stressing my new build at default settings for a few days it passed no problem. I'm taking it gingerly for now - nothing too extreme. Overall I am very pleased with 4.5 GHz, but the damn thermals are just ridiculous.

Worked my way up from 4.4 GHz to 4.6 GHz (all-cores), but I am hitting a 90C wall at 4.6 GHz (~1.218v). I've ultimately settled on 4.5 GHz @ ~1.186v for 24/7. AVX is just too toasty. I get thermal throttling at anything above a -5 offset. It's not the loop either - it never breaks 33C. I settled on a -6 for AVX512 and -5 for AVX. I just can't get the heat out of the package quick enough. I'm not delidded, but I'd image my TIM job is rather poor under there. Silicone-wise it looks like a good win based on the voltages.

I'm using the offset method to get these clocks. -0.064 for 4.5 GHz all-core. Load-Line at Level 3, 140 % current with ASUS Optimized phase control. Using XMP 3200 profile and CPU VCCIN on auto also. Cache all running stock (auto).

System passes a 2-hour RealBench stress run with no throttling - max core temp of 89C. I haven't tested any longer than that except for a 2-hour AIDA64 stress test (CPU-only).

Have you guys experienced any significant temperature decreases from "standard", "optimized" and "extreme" phase profiles?

[Silent_Scone]

Leave phase profiles at defaults, simply increase the current limit. If the CPU has not been delidded, AVX range is limited. You're pulling 300W+ through the die, and you're not able to pull the heat away fast enough. You can set a small offset for cache and keep voltages low. Should be able to reach 3Ghz with 1.05v or less, this can help with temps. Lowering VCCIN whilst checking for stability can help, too.

Short of that, you'll need to delid the CPU.